Characterization of the Topological Structure of the Asphalt Mixture Skeleton Main Force Chain Based on the Complex Network Theory and Discrete Element Method

Abstract The main force chain (MFC) serves as an important tool for analyzing the effective load transfer capacity within the skeleton of asphalt mixture. However, existing studies have not adequately considered the interactions among different MFCs, meaning that the effective transfer loading behavior of the skeleton cannot be fully revealed. The complex network theory is introduced, and the discrete element method (DEM) simulation and indoor experiments were conducted to analyze the topological structure of asphalt mixture skeleton MFC and overcome these shortcomings. The results demonstrate that both the degree value and clustering coefficient effectively capture the characteristics of the MFC network and highlight the significant difference between MFC and non-MFC networks. Moreover, the complex network theory applies to the research on the characteristics of the MFC network. Compared to asphalt concrete (AC) asphalt mixtures, stone mix asphalt (SMA) and open-graded friction course (OGFC) asphalt mixtures have a larger average degree value, and the aggregates in the MFC network are in close contact with each other, enabling the external loading to be transferred effectively. For AC16, an increase in P2.36 reduces the stability of the MFC network, and its content should be limited to within 27%. In the case of SMA16, given thicker pavement structures, an increase in P2.36 will decrease the stability of the MFC network in skeleton-dense asphalt mixtures. Thus, restricting P2.36 to a lower value, such as 15%, is recommended for SMA16. Regarding OGFC16, the MFC network does not exhibit clear regularity with increasing P2.36, suggesting that its behavior is also influenced by pavement structure thickness.